Elements of Biology: A Practical Text-book Correlating Botany, Zoology, and Human PhysiologyAmerican Book Company, 1907 - 445 páginas |
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Página 31
... pollen is produced . It is necessary for the life of the plant that the pollen get out of the anther . Try to find how it gets out . Pistil . Each carpel or pistil is composed of a rather stout base called the ovary , and a more or less ...
... pollen is produced . It is necessary for the life of the plant that the pollen get out of the anther . Try to find how it gets out . Pistil . Each carpel or pistil is composed of a rather stout base called the ovary , and a more or less ...
Página 32
... Pollen . Pollen grains of various flowers , when seen under the microscope , differ greatly in form and appearance . Some are n n ' A pollen grain highly magnified . It contains two nuclei ( n , n ' ) at the stage here represented ...
... Pollen . Pollen grains of various flowers , when seen under the microscope , differ greatly in form and appearance . Some are n n ' A pollen grain highly magnified . It contains two nuclei ( n , n ' ) at the stage here represented ...
Página 33
... pollen has begun to germinate . The cen- tral part of the style is found to be either hollow or composed of a soft tissue through which the pollen tube can easily grow . Upon germina- tion , the pollen tube grows downward through the ...
... pollen has begun to germinate . The cen- tral part of the style is found to be either hollow or composed of a soft tissue through which the pollen tube can easily grow . Upon germina- tion , the pollen tube grows downward through the ...
Página 34
... pollen tube . In flowers in which the style is short , the tube reaches the ovule in the course of a few hours . In plants with a long style , from one to several days may elapse before the pollen tube reaches the locule of the ovary ...
... pollen tube . In flowers in which the style is short , the tube reaches the ovule in the course of a few hours . In plants with a long style , from one to several days may elapse before the pollen tube reaches the locule of the ovary ...
Página 35
... pollen in one flower ; cross - pollination is the transfer of pollen from the anthers of one flower to the stigma of another flower of the same kind . It was found by Charles Darwin and it has since been proved many times that flow- ers ...
... pollen in one flower ; cross - pollination is the transfer of pollen from the anthers of one flower to the stigma of another flower of the same kind . It was found by Charles Darwin and it has since been proved many times that flow- ers ...
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Términos y frases comunes
adapted alcohol American Book Company amount animal arteries attached bacteria bean birds blood vessels bone Botany breathing called carbon dioxide cells color colorless corpuscles containing corn corpuscles cotyledons covered crayfish crustaceans developed dicotyledonous digestive eggs endosperm example experiment fibers fish flower fluid frog fruit germinate gills glands grain green grow growth heart heat Hunter and Valentine insects intestine kidney known laboratory large number larvæ layer leaf leaves legs living lungs Manual material means membrane microscope mollusks monocotyledon mouth muscles muscular nerve nervous system nitrogen Notice organs outer ovary oxidation oxygen parasitic pass Physiology pistil pollen proteid protoplasm root hairs seedlings seeds seen shell side skeleton skin soil species sporangium spores stamens starch stem stomach stomata structure substance sugar surface teeth temperature tiny tion tissues tree veins vertebral vertebral column walls wings worm Zoology
Pasajes populares
Página 397 - Let no youth have any anxiety about the upshot of his education, whatever the line of it may be. If he keep faithfully busy each hour of the working day, he may safely leave the final result to itself. He can with perfect certainty count on waking up some fine morning, to find himself one of the competent ones of his generation, in whatever pursuit he may have singled out.
Página 397 - I won't count this time." Well ! he may not count it, and a kind Heaven may not count it ; but it is being counted none the less. Down among his nerve cells and fibers the molecules are counting it, registering and storing it up to be used against him when the next temptation comes.
Página 397 - Could the young but realize how soon they will become mere walking bundles of habits, they would give more heed to their conduct while in the plastic state. We are spinning our own fates, good or evil, and never to be undone. Every smallest stroke of virtue or of vice leaves its never so little scar. The drunken Rip Van Winkle, in Jefferson's play, excuses himself for every fresh dereliction by saying, 'I won't count this time!
Página 321 - He flavors his food with salt,' is to imply that he is rich, and children will suck a piece of rock-salt as if it were sugar. No stronger mark of respect or affection can be shown in Muscovy, than the sending of salt from the tables of the rich to their poorer friends.
Página 397 - The hell to be endured hereafter, of which theology tells, is no worse than the hell we make for ourselves in this world by habitually fashioning our characters in the wrong way.
Página 403 - The more purely intellectual qualities of the mind rarely escape being involved in the general disturbance [caused by alcohol]. The power of application, of appreciating the bearing of facts, of drawing distinctions, of exercising the judgment aright, and even of comprehension, are all more or less impaired. The memory is among the first faculties to suffer. . . . The will is always lessened in force and activity. The ability to determine between two or more alternatives, to resolve to act when...
Página 61 - Jimson weed, to the exclusion of all other forms of plant life. That this is not the case is due to the fact that only those seeds which are advantageously placed can develop ; the others will, for various reasons (lack of moisture to start the young seed on its Grain ; spikes of ened flowers.
Página 321 - No stronger mark of respect or affection can be shown in Muscovy, than the sending of salt from the tables of the rich to their poorer friends. In the book of Leviticus it is expressly commanded as one of the ordinances of Moses, that every oblation of meat upon the altar shall be seasoned with salt, without lacking ; and hence it Is called the Salt of the Covenant of God. The Greeks and Romans also used salt in their sacrificial cakes ; and it is still used in the services of the Latin church—...
Página 397 - Well! he may not count it, and a kind Heaven may not count it; but it is being counted none the less. Down among his nerve cells and fibers the molecules are counting it, registering and storing it up to be used against him when the next temptation comes. Nothing we ever do is, in strict scientific literalness, wiped out. Of course, this has its good side as well as its bad one. As we become permanent drunkards by so many separate drinks, so we become saints in the moral, and authorities and experts...
Página 103 - The sap carries water and plant-foods from the roots to the leaves and from the leaves to the growing parts of the tree. That is why it is so important to keep the bark from being injured, for if the bark is cut or bruised or bored into by insects, the tree loses sap and is weakened. 8.